A three-dimensional measurement apparatus that employs a slit ray projection method (also known as a light chopping method) is known in the prior art, as disclosed, for example, in Japanese Patent Unexamined Publication No. 9-196632. The slit ray projection method is a method for obtaining a three-dimensional image (range image) by optically scanning an object, and is a form of active measurement method that photographs an object by projecting a specific reference beam on it. The slit ray projection method uses a slit ray whose cross section is a straight line.
When performing a three-dimensional measurement, the purpose of the measurement can vary in different ways. There are many situations according to the purpose; for example, one may want to make the measurement at high speed and in the shortest possible time, or may want a high resolution measurement at some sacrifice of the measuring speed, or may want to measure an object having a large depth.
However, according to the prior art three-dimensional measurement apparatus, it has only been possible to make measurements for the purpose that matches the specification of the three-dimensional measurement apparatus. For example, the measuring speed, the measurable dimension in the depth direction, the resolution, etc. have been predetermined as specifications, and it has not been possible to cope with situations that require significant changes in the measuring conditions, such as when one wants to make measurements at higher speed or with a higher resolution. Accordingly, in the prior art, it has been necessary to purchase different three-dimensional measurement devices for different measurement purposes.
The present invention has been devised in view of the above problem, and it is an object of the invention to provide a three-dimensional measurement apparatus which can accommodate multiple different measurement conditions to address various measurement purposes.